Association Between Serum Total Bilirubin Levels and the Morphology of Corneal Nerve Fibers in Japanese Patients With Uncontrolled Type 2 Diabetes

Oxidative stress (OS) plays a key role in the development of diabetes complications. Bilirubin is a potent antioxidant, and serum total bilirubin (TB) levels in the low-normal range are associated with diabetic retinopathy (1) and nephropathy (2) and are predictive of lower-limb amputation (3). However, the relationship between serum TB and diabetic neuropathy has not been reported. Due to constant exposure to OS (sunlight and ambient air) and poor antioxidant activity due to its avascularity, the cornea is vulnerable to OS (4). Diabetes increases the OS burden on the cornea. Corneal nerve fibers (CNFs) are composed of unmyelinated C-fibers, which are the first nerve fibers to undergo damage and subsequent repair. We examined the association between serum TB and CNF morphology in patients with uncontrolled type 2 diabetes (T2D).Cross-sectional data were collected from 384 …